Prevention of vehicle and vehicle accessory theft has been a widespread concern among vehicle owners and users. Ignition locks and door locks with which vehicles are equipped by the manufacturer are but a weak deterrent to the vehicle thief.
Auxiliary locking devices which are portable in nature have been proposed to immobilize vehicles and to increase the difficulty through which the thief must go to render a vehicle capable of being removed Such devices have been proposed in the form of tire locking clamps and blocks to inhibit the movement of vehicle wheels, as well as steering wheel locks to restrict the use of the vehicle's steering mechanisms. The function provided by these prior art locking devices has been to prevent some thieves from stealing certain vehicles by requiring increased effort to defeat these locking devices.
Portable steering wheel locks, for example, have been proposed which can be locked to a vehicle steering wheel so as to limit the rotatability of the steering wheel and thus the driveability of the vehicle. Such devices are, for example, shown in U.S. Pat. Nos. 1,429,334 of Furber, 4,444,030 of Dausch and 4,829,797 of Wu. Defeat of such locking devices by a thief requires an increase in time and effort in the removal of the vehicle. Such devices can be, and often are, broken, cut or otherwise defeated, and the vehicle thus ultimately stolen. Even when effective in preventing theft, the vehicles in which they are installed frequently suffer damage, in the form of broken windows or the mutilation of doors and door locks, or the removal of vehicle accessories. Portable steering wheel locks of the prior art have had many and various disadvantages, including being generally cumbersome, inconvenient to attach to and detach from the steering wheel, insufficiently visible to discourage break-ins, and relatively easy to pick, cut or otherwise remove from the vehicle. They also lack the capability of providing an alarm to focus attention on the actions of the would-be thief.
An alternative approach to portable locks which has been increasingly used to reduce vehicle theft, has been the use of vehicle alarms. Such alarms are usually built into the vehicle and function by activating a siren or other alarm indicator in response to some detected action by a thief such as the breaking into a vehicle, motion of the vehicle or of a vehicle component, etc. Vehicle alarms have also been known which are responsive to the movement of the vehicle steering wheel, as shown in, for example, Fassett U.S. Pat. No 1,139,757.
Vehicle alarms of the prior art, as noted, are commonly permanently installed in the vehicle. As such, they have the disadvantage of protecting only a single vehicle, and cannot be moved from vehicle to vehicle when the owner drives several vehicles on an alternating basis or conveniently installed in a different vehicle when the owner sells or trades in his vehicle for a new one. Alarm systems which are permanently installed in specific vehicles are substantially more expensive than are portable alarms, most of the cost being that associated with the alarm system's installation rather than that associated with the alarm equipment itself. Since installed alarm systems protect a single vehicle, owners of more than one vehicle are required to purchase more than one alarm system if protection of more than one vehicle is desired. Furthermore, installed alarm systems of the prior art have been prone to installation errors and have a reputation for generating frequent false alarms and experiencing frequent system malfunctions. In addition, most installed alarms do not provide clear evidence to the thief that an alarm is present and armed within the vehicle. Accordingly, such alarm systems of the prior art do not effectively deter a thief until the alarm is sounded which may follow the infliction by the thief of significant damage to the vehicle.
Permanently installed automobile alarm systems generally have been inconvenient to install and use and are quite costly. This inconvenience and cost has deterred many automobile owners from installing and using such alarms.
The prior art has failed to provide an economical, and sufficiently light weight and portable, anti-theft device which can be easily attached to and removed from a vehicle by the owner, but which is highly resistant to unauthorized removal by a thief, and which is visible enough from the exterior of the vehicle to deter forced entry. Such devices of the prior art fail to provide a high degree of security for the vehicle, as well as for accessories within the vehicle, and fail to adequately protect against the destruction and removal of the locking device itself. The prior art has been particularly deficient in providing a portable locking device which can be easily attached to and removed from a vehicle by the owner but not by a thief, and which combines the signalling and deterrent advantages of an effective alarm with those of a portable vehicle locking device.
Furthermore, the features of vehicle alarms have not been provided or suggested in portable locking devices. The problems inherent in equipping such portable locking devices with alarms have, accordingly, not been addressed by the prior art. These problems include the protection of the alarm circuit itself from the tampering to which it would be exposed in a portable device and in providing a tamperproof power source adequate to power the alarm, particularly for vehicles not equipped with cigarette lighter power receptacles that are powered when the ignition is off. Particularly, the prior art has not provided a locking device having alarm features which are both tamperproof and adequately powered to provide full monitoring and alarm capabilities, and which does so without reliance upon the power source of the electrical system of the vehicle being protected.
Accordingly, there is a need for a portable vehicle anti-theft device which provides a high level of vehicle security, and which in an optional, preferred form combines the theft deterrent locking features of steering wheel locks with the full alarm capabilities heretofore found only in permanently installed alarm systems.